con rod bearing sets...

[Morrisbear]

I dont know much about engines but was looking through esm's website and noticed 1098 con rod bearing sets. are these what they mean by main bearings? anyway, it is strange some sets are 80 pounds or whatever, and some sets are 12 pounds? what is the difference... just quality?

[bmcecosse]

Con rod bearings are the shell bearings for the con rod big ends. Main bearing shells are also needed - to carry the crankshaft in the block. There are also small thrust bearings - to take the end load imposed on the crankshaft by the clutch action, and generally to restrain the crankshaft within the block. I'm guessing they may be the £12 set........ Are you planning to use any of these bearings ??

[JOWETTJAVELIN]

Cost depends v. much on the engine - parts for early versions(sidevalve, 803, 948) are thin on the ground and cost more as a result.

I had to go to a specialist for some 40 thou. oversize big-end bearings for the 803 as none of the usual suppliers had any left; cost me about £70 inc. VAT.

[Morrisbear]

no not using them but trying to leanr a bit about engines and was confused by pricing. having reread the esm site though it seems that it is 12 pounds for con'rod bearings for 1098 engines, but more expensive for older engines so that's why there was a price difference

[bmcecosse]

Well yes -that could be so. Little demand for the older/smaller bearings on an 803 engine - so it's not worthwhile for the manufacturer to spend the time setting up a line of presses to bang them out, and then tear the set-up down again. Years ago I made these bearings at Glacier........there were rumours of presses being set up on the nightshift to run off a few odd sets as 'homers' - but I was not party to any of that! The 848 and 948 and 1098 Minor engines (and 848/997/998/1098 Mini engines) all use the same shells (except the Spridget 10CC versions of the 1098...) so there is good economy of scale running off these shells. And so the cost is less!

[JOWETTJAVELIN]

I can't understand why current 803 bearings aren't made in a more durable material, like the later ones, rather than white metal.

[bmcecosse]

Simply because of the excruciating low demand. They will be almost hand made by a much simpler process. You should have fitted a 948 crank and rods..........

[JOWETTJAVELIN]

There's always the next time.